Work machines such as backhoes, excavators, and other work machines have a variety of work implements that are hydraulically operated via one or more operator control devices. The operator control devices may have a particular movement pattern that corresponds to movement of associated work implements. These movement patterns for similar work implements may be different between work machines. For example, a forward tilting movement of a right hand joystick in an excavator arrangement may result in a downward movement of an associated boom, while a forward tilting movement of a left hand joystick in a backhoe arrangement may result in a similar downward movement of the boom. Likewise, a forward tilting movement of the left hand joystick in the excavator arrangement may result in a downward movement of an associated stick, while a forward tilting movement of the right hand joystick in the backhoe arrangement may result in a similar downward movement of the stick. Because of the movement pattern differences between work machines, an operator having experience in an excavator, for example, may find it difficult to efficiently operate a backhoe and, likewise, a backhoe-experienced operator may find it difficult to efficiently operate an excavator.
One method of reducing confusion and efficiency loss associated with the different movement patterns between the operator control devices of different work machines is to implement a switching valve that switches the movement patterns between operator control devices according to operator preference. One such device is described in U.S. Pat. No. 4,986,165 (the '165 patent) issued to Miyaoka on Jan. 22, 1991. The '165 patent describes a hydraulic shovel operating apparatus for operating a plurality of control valves, which control the operation of work devices. The operating apparatus includes a pattern switching valve having a rotary spool inserted into a casing that is remotely located on the hydraulic shovel and connected between pilot and control valves of the hydraulic shovel via hydraulic pipes. The rotary spool may be manually rotated through a predetermined angle to establish differing valve connection patterns of the pilot and control valves.
Although the operating apparatus of the '165 patent may increase operator ease and work efficiency by providing multiple valve connection patterns, the operating apparatus may be expensive, space consuming, and inconvenient for the operator. In particular, because the operating apparatus is remotely located, unique additional mounting hardware and fluid routing components are required that increase the cost of the work machine. Further, because the operating apparatus is remotely located, space on the work machine that might be used for other purposes is consumed, thereby limiting design flexibility of other work machine systems. In addition, because the operating apparatus must be manually rotated to make the valve connections, switching between the various valve connection patterns may be time consuming and inconvenient for the operator.
The disclosed valve stack is directed to overcoming one or more of the problems set forth above.